Grinding apparatus mounted on an overhanging shaft



April 20, 1948. UND ET AL 2,440,051

GRINDING APPARATUS MOUNTED ON AN OVERHANGING SHAFT Filed Nov. 22, 1943 1N VENT OR-s ATTORNEY.

. grinding element is mounted Patented Apr. 20, 1948 GRINDING APPARATUS MOUNTED ON AN OVERHANGING SHAFT Arthur C. Lind and Rober Wis., assignors to Cha t E. Klein, Milwaukee,

in Belt Company, Milwaukee, Wis., a corporation of Wisconsin Application November 22, 1943, Serial No. 511,238

3 Claims. (01. 24143) This invention relates to a grinding device which because of its compact form and unique design may be employedin kitchens-for grinding garbage such as vegetables, meats and small bones. Heretofore grinders have been built for home use and to aid in garbage disposal but such grinders have not been sufliciently rugged or lack the capacity to permit their use in commercial establishments such as hotels and restaurants. Grinders of the type used in industrial processing have not been satisfactory for this intermediate field either, because of their lack of efllciency, high initial cost and inability to stand up for a suiiicient length of time when employed under such arduous service conditions.

To successfully meet the problem of grinding kitchen garbage in quantity, the machine must be capable of handling a great variety of materials. Fruit peelings, vegetable peelings, v pieces of paper or cardboard, meat, bones, table scraps and even silverware or crockery are apt to be fed into the grinder, and while some of this material might be screened or sorted out, such procedure would be disagreeable and would delay quick disposal of the refuse.

It is an object of the present invention to provide a grinding machine in which there are means for protecting the operating parts from the excessive strains which would otherwise result should some foreign element such as silverware enter the grinding compartment.

A further object of the invention is to provide a grinder which without occupying very large space can nevertheless handle considerable quantity of material, one which will not be stalled easily and which will operate smoothy and with a very low power consumption.

More specifically, it is an object of this invention to provide grinding apparatus in which the on an overhanging shaft and in which the end of the shaft may have occasional bearing support in the event of certain conditions in grinding operations.

An additional object of the invention is to provide a garbage grinder in which the parts are so assembled and designed. that the unit may be readily cleaned out, parts removed and grinding surfaces reground so as to extend the useful life of the machine.

These and other objects of the invention will be better understood after consideration of the following detailed description and the claims appended thereto taken in connection with the accompanying drawings.

In the drawings, Figure 1 is an elevation view,

partly in section, showing the end of the grinding device; Figure 2 is a section taken on the line 22 of Figure 1; Figure 3 is a perspective view of the rotor assembly removed from the housing; and Figure 4 is a perspective view of the hand crank used to turn the rotor when the motor is not in operation.

From an inspection of the drawings, it will be seen that the various elements making up the unit have been'arranged in a compact form so as to enable it to be mounted under a sink or on a small table such as is indicated by the dotted lines in Figure 2. This is made possible by a unique arrangement for mounting of the various elements on the motor shaft including the elimination of outboard hearings on both sides of the cutting element, and also by the goose-neck feeding arrangement, each of which will be hereinafter described in detail.

In the feeding arrangement shown in the drawings, there is a substantially vertical sheet metal duct I00 disposed above the motor and discharging into an elbow portion IOI having an inclined lower surface I02 down which the material may slide when passing to the grinder. Duct I00 has a flange surrounding-its top opening with apertures spaced around the flange to permit firm securement to the top of a table, sink or other working surface indicated by the dotted line B. A swill block of rubber or similar material indicated by the dotted lines A may be placed over the inlet of the duct I00, said duct being slightly tapered downwardly in order that a flange on such block may be gripped by the side of the duct when the former is inserted in the opening. This block which is conventional'and forms no part of the present invention serves as a surface against which the edges of the dishes may be struck to loosen material resting on them, the food or refuse falling through the block into the opening I00.

The lower end of the elbow member IOI is flanged and bolted onto the grinder housing I03 the end of which is apertured to retain an annu lar, flanged cover plate I04 rigidly secured thereto by bolts I05. The flanged portion I06 of the cover plate provides a surface exterior to the housing through which the bolts may be extended and the inner side of the end wall of the housing are flush with the inner side of the .cover plate. An annular groove is provided on this inner side of the cover plate for reception of a sealing ring on the cutter rotor, said groove being sufficiently deep to form not only an extended sealing surface but also .a radial bearing surface should the rotor shaft deflect under load conditions. Normally, however, there is no bearing load on the cover plate but a close running fit is provided between its groove and the rotor to seal the opening against escape of material being ground. The central portion of the cover plate may be somewhat dished outwardly as at I01 to house the outer end of the rotor shaft, and a. grease fitting I08 is provided in this dished portion, it being desirable that the space between the end of the rotor and the cover plate should be completely filled with grease.

The lower portion of a housing I03 is tapered into tubular form and leads downwardly at an angle from beneath the rotary cutter, the tubular end being threaded for securement to a pipe fitting through which the ground garbage is discharged. It will be seen from Figure ,1 that the inlet to the grinder housing is disposed over the second quadrant of the rotor surface whereas the outlet is disposed so as to receive material approximately. evenly from the entire lower half of the rotor. It will also be clear from reference to Figure 2 that the rotor housing has an inner surface defined by an inclined plate I09, the lower portion of which terminates in a horizontal edge parallel to the axis of the rotor at the margin between the second and third quadrants of the latter. The first quadrant of the rotor is totally enclosed by semicylindrical surface H in fairly close proximity to the periphery of the rotor. The underside, or third and fourth quadrants of the rotor, are enclosed by a semicylindrical grate III, of hardened steel or other suitable material having a number of apertures closely spaced apart and with sharply defined edges to promote shearing action in cooperation with the rotor teeth. Grate or screen III rests in grooves formed in, the end walls of housing I03 and is additionally supported at its mid point by a steel rib I I2 extending longitudinally across the housing. With this construction when the edges on one side of the perforations in the screen I ll become worn, the screen may be turned around so that the rotor teeth may out against the opposite edges of the perforations, thereby prolonging the useful life of the cutting surface.

From the foregoing it will be appreciated that the means for feeding garbage into the grinder comprises a. plurality of passageways eventually feeding into the second quadrant of the rotor housing. As the rotor comes in contact with the screen ill at the margin between the second and third quadrants a wedging action may take place which, due to the very high speed of the rotor (as high as 3600 R. P. M.) may cause material to be shot upwardly through the inlet passage. Such material is baffled by the surfaces defining the inlet passageway so instead of coming through the outlet I00, it is returned tothe grinder.

The rotor cutter H3 comprises a plurality of discs lid concentrically arranged about and fournalled on a rotor shaft H5 which is an extension of the same rotor shaft of the electric motor furnishing the power. Each of the discs, with the exception of the two end discs I I0,,have teeth profiles formed in their outer peripheries, said profiles consisting of a radial cutting edge Ill approximately one-fourth the maximum radius of the discs and a rake portion gradually receding inward to the root of the next tooth. The curvature of this receding portion is approximately equal to the curvature of the screen basket III and affords a pocket of sumoient length and depth to permit rapid grinding or the garbage. The peripheral cutting edges, which extend axially for the full width of the disc, are set. only a few thousandths of an inch from the screen I I I so as to promote shearing action therebetween; a slight clearance however, is desirable'for quietness of operation when the grinder is running empty.

The end discs IIG are of slightly larger diameter than the cutter discs, the diameters being such that they may afford a close running fit as previously described in the grooves formed in the end plates of the housing. the width of these discs H6 being approximately equal to the depth of saidgrooves, whereby the cutting discs disposed between the end discs may occupy the full length of the internal portion of the housing.

The entire cutter assembly including the end discs is retained together as a unit by a plurality of cap screws IIB with head portions countersunk flush with the end Of the discs, the shank ends being threaded into the sealing disc at the opposite end of the assembly. The cutting discs are arranged so that the cutting teeth are staggered, preferably in herringbone fashion, with the cutting edges of behind the cutting edges of these discs nearer the ends of the rotor. This arrangement, which is best illustrated in Figure 3, promotes rapid movement of material into the grinder since there is a V-shaped pocket produced by the rake of the Various teeth with the apex at the center of the rotor tending to drag material into the grinding case. a

The rotor assembly I I3 is not keyed to the rotor shaft H5 but is prevented from rotating with respect thereto by means of friction between a friction washer I I9 retained by a lock washer I20 cooperating with a lock nut I2I the latter being threaded on the end of the rotor shaft Iii. While the friction washer restrains the rotor from turning on its shaft during the normal grinding operation. should a piece of silver, or metal, manage to enter the grinder the impact of the rotor is cushioned by the possible slippage between the rotor and the shaft. and the shaft is protected from the sudden torque which would be developed if it were brought to rest immediately upon the locking of the cutter in its cage.

Rotor shaft H5 is supported by a pair of bearings I22 retained in races I23 supported by the motor frame I24.- The mounting of-the grinder housing on the motor frame is such that parts may be readily disassembled should the latter become necessary, This construction includes a flanged end bell I25 bolted or otherwise secured to the motor frame, said end bell having a face against which may be seated the inner end of the rotor housing, said parts being secured together by means of cap screws I26. Within the space behind the end sealing disc on the motor side are a plurality of countersunk apertures for receiving cap bolts I21 threaded into a bearing cap I28, the latter retaining bearing race I23. Bearing cap I28 is provided with a seal I29 enclosing the shaft at a point between the bearing and the motor. Labryinth grease seals I30 are provided on the opposite side of the bearing between the shaft and the bell and directly behind the inner disc H6. Grease fitting I3I communicating with bearing I22 enables the space between the inner end of the rotor and the bearing to be packed with grease at frequent intervals. Shaft H5 is stepped down from the motor to the rotor with a threaded portion enga ed by the medially disposed discs a lock nut I32 cooperating with a shoulder I33 on the shaft to retain the bearing race, a second shoulder I 34 forming a seat preventing end displacement of the grinding rotor assembly. Figure 2 illustrates how the rotor shaft II 5 is extended through the motor on the opposite side from the rotor cutter, there being a similar bearing and seal construction to that described in the preceeding paragraph. The end of the shaft I35 in this instance however extends beyond the housing and is provided with such an exterior configuration that it may be gripped by a hand crank I36 (shown in Figure 4) and the rotor held against turning during the removal of the lock nut I2I at th opposite end should it be desired to remove the rotor. Conversely the hand crank may be used to manually turn the rotor should it be desirable to do so. End portion I35 is enclosed by a hub cap I31 which can be readily removed when hand crank I36 is to be employed.

To assist in the grinding operation and to flush material through the perforated cage I II a source of water is connected with a spray pipe I38 which extends horizontally at the junction between the inclined portion I02 of the feed passageway and inlet duct I00. This spray pipe has a series of perforations extending longitudinally thereof which direct water down the inclined surface I02 and assists in charging the material uniformly into the grinder. Flushing water should be flowing through the grinder before material is fed into it and with a grinder adapted to handle approximately four hundred pounds of garbage per hour, approximately four gallons of water per minute should be employed. Excess water tends to flood the grinding compartment and increases the power consumption.

As previously stated, the feeding apparatus is such that it will prevent garbage from being thrown back by the rotary cutter and is also of such length and contour as to make it difficult for an operator to reach down through the feed inlet and touch the cutter while it is in operation. Such garbage as is thrown upwardly by the rotor is confined by the upper surface I39 of the elbow shaped feed inlet. Further baiiling-is produced by a deflecting partition I40 forming an' teeth is such that they may be reground radially without grinding the arc of the tooth, the same rake being maintained at all times. Due to the slight rake which is employed, this cutting edge may be reground several times without appreciably diminishing the clearance between the edge of the teeth and the grinding cage III. Should this clearance become too great however, the cage may be easily shimmed up to provide close clearance.

Should it be necessary to replace or repair the front motor bearing, the same operations are performed, including the removal of the rotor assembly, thereby making accessible the cap bolts I21 which secure the end'bell I25 to the bearing cap I28. Removal of cap bolts -I2'I, cap screws I26 and also the nuts which fasten the flange end bell to the motor permits removal of the entire housing, the flanged end bell and the oil seals I29, thereby exposing the front motor bearing for repair or replacement. To reassemble the unit these operations are performed in reverse order.

Despite the high speed of the rotor, the pockets formed ahead of the cutting edges are sum- 'ently long and deep to permit material to enter the space between the cutting edges of the rotor and the grinding cage. With the rotor operating at a speed of 3500 R. P. M., a three tooth cutter of only flve inch diameter shaped in the precise manner described and illustrated herein can handle upwards of four hundred pounds of garbage per hour, and one and one-half horsepower motor is sufficiently powerful to handle the material at this rate. While the invention is not limited to precise details of construction, the foregoing detailed illustration of an embodiment of the invention will illustrate the practice thereof.

The invention having been described, what is claimed is:

1. In a grinding machine, a, rotor shaft and a grinding element journalled on said shaft, a

extension of one side of the feed inlet and separating the feed inlet and the elbow portion IOI, It should be observed that the elbow shaped feed inlet is arranged parallel to the axis of the rotor and feeds into that side of the rotor wher the rotor is moving awayv from the feed duct.

Should the machine stall due to an overloading of material, it is possible through the use of the hand crank I36 to rock the rotor back and forth while the unground garbage is being removed. The bolted connection between the feed portion II'II and the housing proper, I03, permits ready access to the cutting compartment to facilitate removing material in such instances.

Should one want to disassemble the unit, the operator flrst removes the bolts retaining the flanged cover plate. At this stage it is possible to slide the cutting screen directly out from beneath the rotor so that it may be cleaned if need be, or turned end for end to present,the unused cutting edges of the perforations as a cutting surface should the opposite edges have become dulled through use. Should it be desirable to remove the rotor the hand crank I 36; is employed to prevent the rotor shaft from turning and the lock washer I20 and friction gasket I2I are removed and the entire rotor assembly H3 is slid off the shaft. The design of the rotor cutting griding housing enclosing said grinding element and having a grinding surface cooperating with said grinding element to produce grinding action, bearings supporting said shaft at one side of said grinding element only, frictional means cooperating with said shaft and grinding element providing yieldable connection therebetween, and a cover plate secured to said housing enclosing the unsupported end of said shaft, said cover plate having an axially disposed surface sealing said grinding element and arranged to provide bearing support should the shaft deflect under grinding loads.

2. In a grinding machine. a rotor shaft, and a grinding element journalled on said shaft, said element composed of disc members assembled and looked as a unit, a housing enclosing said grinding element and having a grinding surface cooperating with said grinding element to produce grinding action, bearings supporting said shaft in an overhanging manner, friction means cooperating with said shaft and grinding element causing them to rotate together, and a cover plate secured to said housing enclosing the unsupported end of said shaft, said cover plate having an axially disposed surface sealing said grinding element and arranged to provide bearing support for the shaft through the friction means should the shaft deflect under grinding loads.

3. In a rotary grinder, a rotor shaft, an enclosing grinding housing, a grinding surface in said housing, a unitary rotary grinding element Journalled on said shaft, arranged to provide .grinding action with said surface, said element including individual plates locked together and having cutting edges on-their peripheries, bearin s supporting said shaft in overhanging relationship, frictional means cooperating with said shaft and grinding element providing yieldable connection therebetween, and a cover plate secured to said housingenclosing the unsupported end of said shaft, said cover plate having an axially disposed surface sealing said grinding element and arranged to provide bearing support should the shaft deflect undergrinding loads.

ARTHUR C. LIND. ROBERT E. KLEIN.

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